New sub-path export @alkdev/pubsub/call providing:
- CallEventSchema (TypeBox schemas) for call.requested/responded/part/completed/aborted/error
- PendingRequestMap with call() (request/response) and subscribe() (streaming via Repeater)
- CallError class and CallErrorCode constants
- Scoped topic subscriptions (call.responded:{requestId}) to avoid O(n) fanout
- subscribe() yields call.part events until call.completed or call.error,
with automatic call.aborted on consumer break
Also adds @alkdev/typebox as runtime dependency and architecture doc.
Port the core Repeater class (push/stop executor, async iterator protocol,
overflow protection) from @repeaterjs/repeater into src/repeater.ts, stripping
buffers and combinators we don't use. This removes the 7-year-old dependency
while keeping the same API surface for all current and future adapters
(Redis, WebSocket, SSE, Iroh).
Also add the async utility research doc for reference.
